Implement PEP 393.

1 files changed, 1439 insertions, 6 deletions

diff --git a/Python/formatter_unicode.c b/Python/formatter_unicode.c
index c350907..9fb840b 100644
--- a/Python/formatter_unicode.c
+++ b/Python/formatter_unicode.c
@@ -3,12 +3,1445 @@
    of int.__float__, etc., that take and return unicode objects */
 
 #include "Python.h"
-#include "../Objects/stringlib/unicodedefs.h"
+#include <locale.h>
 
+/* Raises an exception about an unknown presentation type for this
+ * type. */
 
-#define FORMAT_STRING  _PyUnicode_FormatAdvanced
-#define FORMAT_LONG    _PyLong_FormatAdvanced
-#define FORMAT_FLOAT   _PyFloat_FormatAdvanced
-#define FORMAT_COMPLEX _PyComplex_FormatAdvanced
+static void
+unknown_presentation_type(Py_UCS4 presentation_type,
+                          const char* type_name)
+{
+    /* %c might be out-of-range, hence the two cases. */
+    if (presentation_type > 32 && presentation_type < 128)
+        PyErr_Format(PyExc_ValueError,
+                     "Unknown format code '%c' "
+                     "for object of type '%.200s'",
+                     (char)presentation_type,
+                     type_name);
+    else
+        PyErr_Format(PyExc_ValueError,
+                     "Unknown format code '\\x%x' "
+                     "for object of type '%.200s'",
+                     (unsigned int)presentation_type,
+                     type_name);
+}
 
-#include "../Objects/stringlib/formatter.h"
+static void
+invalid_comma_type(Py_UCS4 presentation_type)
+{
+    if (presentation_type > 32 && presentation_type < 128)
+        PyErr_Format(PyExc_ValueError,
+                     "Cannot specify ',' with '%c'.",
+                     (char)presentation_type);
+    else
+        PyErr_Format(PyExc_ValueError,
+                     "Cannot specify ',' with '\\x%x'.",
+                     (unsigned int)presentation_type);
+}
+
+/*
+    get_integer consumes 0 or more decimal digit characters from an
+    input string, updates *result with the corresponding positive
+    integer, and returns the number of digits consumed.
+
+    returns -1 on error.
+*/
+static int
+get_integer(PyObject *str, Py_ssize_t *pos, Py_ssize_t end,
+                  Py_ssize_t *result)
+{
+    Py_ssize_t accumulator, digitval, oldaccumulator;
+    int numdigits;
+    accumulator = numdigits = 0;
+    for (;;(*pos)++, numdigits++) {
+        if (*pos >= end)
+            break;
+        digitval = Py_UNICODE_TODECIMAL(PyUnicode_READ_CHAR(str, *pos));
+        if (digitval < 0)
+            break;
+        /*
+           This trick was copied from old Unicode format code.  It's cute,
+           but would really suck on an old machine with a slow divide
+           implementation.  Fortunately, in the normal case we do not
+           expect too many digits.
+        */
+        oldaccumulator = accumulator;
+        accumulator *= 10;
+        if ((accumulator+10)/10 != oldaccumulator+1) {
+            PyErr_Format(PyExc_ValueError,
+                         "Too many decimal digits in format string");
+            return -1;
+        }
+        accumulator += digitval;
+    }
+    *result = accumulator;
+    return numdigits;
+}
+
+/************************************************************************/
+/*********** standard format specifier parsing **************************/
+/************************************************************************/
+
+/* returns true if this character is a specifier alignment token */
+Py_LOCAL_INLINE(int)
+is_alignment_token(Py_UCS4 c)
+{
+    switch (c) {
+    case '<': case '>': case '=': case '^':
+        return 1;
+    default:
+        return 0;
+    }
+}
+
+/* returns true if this character is a sign element */
+Py_LOCAL_INLINE(int)
+is_sign_element(Py_UCS4 c)
+{
+    switch (c) {
+    case ' ': case '+': case '-':
+        return 1;
+    default:
+        return 0;
+    }
+}
+
+
+typedef struct {
+    Py_UCS4 fill_char;
+    Py_UCS4 align;
+    int alternate;
+    Py_UCS4 sign;
+    Py_ssize_t width;
+    int thousands_separators;
+    Py_ssize_t precision;
+    Py_UCS4 type;
+} InternalFormatSpec;
+
+#if 0
+/* Occassionally useful for debugging. Should normally be commented out. */
+static void
+DEBUG_PRINT_FORMAT_SPEC(InternalFormatSpec *format)
+{
+    printf("internal format spec: fill_char %d\n", format->fill_char);
+    printf("internal format spec: align %d\n", format->align);
+    printf("internal format spec: alternate %d\n", format->alternate);
+    printf("internal format spec: sign %d\n", format->sign);
+    printf("internal format spec: width %zd\n", format->width);
+    printf("internal format spec: thousands_separators %d\n",
+           format->thousands_separators);
+    printf("internal format spec: precision %zd\n", format->precision);
+    printf("internal format spec: type %c\n", format->type);
+    printf("\n");
+}
+#endif
+
+
+/*
+  ptr points to the start of the format_spec, end points just past its end.
+  fills in format with the parsed information.
+  returns 1 on success, 0 on failure.
+  if failure, sets the exception
+*/
+static int
+parse_internal_render_format_spec(PyObject *format_spec,
+                                  Py_ssize_t start, Py_ssize_t end,
+                                  InternalFormatSpec *format,
+                                  char default_type,
+                                  char default_align)
+{
+    Py_ssize_t pos = start;
+    /* end-pos is used throughout this code to specify the length of
+       the input string */
+#define READ_spec(index) PyUnicode_READ_CHAR(format_spec, index)
+
+    Py_ssize_t consumed;
+    int align_specified = 0;
+
+    format->fill_char = '\0';
+    format->align = default_align;
+    format->alternate = 0;
+    format->sign = '\0';
+    format->width = -1;
+    format->thousands_separators = 0;
+    format->precision = -1;
+    format->type = default_type;
+
+    /* If the second char is an alignment token,
+       then parse the fill char */
+    if (end-pos >= 2 && is_alignment_token(READ_spec(pos+1))) {
+        format->align = READ_spec(pos+1);
+        format->fill_char = READ_spec(pos);
+        align_specified = 1;
+        pos += 2;
+    }
+    else if (end-pos >= 1 && is_alignment_token(READ_spec(pos))) {
+        format->align = READ_spec(pos);
+        align_specified = 1;
+        ++pos;
+    }
+
+    /* Parse the various sign options */
+    if (end-pos >= 1 && is_sign_element(READ_spec(pos))) {
+        format->sign = READ_spec(pos);
+        ++pos;
+    }
+
+    /* If the next character is #, we're in alternate mode.  This only
+       applies to integers. */
+    if (end-pos >= 1 && READ_spec(pos) == '#') {
+        format->alternate = 1;
+        ++pos;
+    }
+
+    /* The special case for 0-padding (backwards compat) */
+    if (format->fill_char == '\0' && end-pos >= 1 && READ_spec(pos) == '0') {
+        format->fill_char = '0';
+        if (!align_specified) {
+            format->align = '=';
+        }
+        ++pos;
+    }
+
+    consumed = get_integer(format_spec, &pos, end, &format->width);
+    if (consumed == -1)
+        /* Overflow error. Exception already set. */
+        return 0;
+
+    /* If consumed is 0, we didn't consume any characters for the
+       width. In that case, reset the width to -1, because
+       get_integer() will have set it to zero. -1 is how we record
+       that the width wasn't specified. */
+    if (consumed == 0)
+        format->width = -1;
+
+    /* Comma signifies add thousands separators */
+    if (end-pos && READ_spec(pos) == ',') {
+        format->thousands_separators = 1;
+        ++pos;
+    }
+
+    /* Parse field precision */
+    if (end-pos && READ_spec(pos) == '.') {
+        ++pos;
+
+        consumed = get_integer(format_spec, &pos, end, &format->precision);
+        if (consumed == -1)
+            /* Overflow error. Exception already set. */
+            return 0;
+
+        /* Not having a precision after a dot is an error. */
+        if (consumed == 0) {
+            PyErr_Format(PyExc_ValueError,
+                         "Format specifier missing precision");
+            return 0;
+        }
+
+    }
+
+    /* Finally, parse the type field. */
+
+    if (end-pos > 1) {
+        /* More than one char remain, invalid conversion spec. */
+        PyErr_Format(PyExc_ValueError, "Invalid conversion specification");
+        return 0;
+    }
+
+    if (end-pos == 1) {
+        format->type = READ_spec(pos);
+        ++pos;
+    }
+
+    /* Do as much validating as we can, just by looking at the format
+       specifier.  Do not take into account what type of formatting
+       we're doing (int, float, string). */
+
+    if (format->thousands_separators) {
+        switch (format->type) {
+        case 'd':
+        case 'e':
+        case 'f':
+        case 'g':
+        case 'E':
+        case 'G':
+        case '%':
+        case 'F':
+        case '\0':
+            /* These are allowed. See PEP 378.*/
+            break;
+        default:
+            invalid_comma_type(format->type);
+            return 0;
+        }
+    }
+
+    if (format->fill_char > 127 || format->align > 127 ||
+        format->sign > 127) {
+        PyErr_SetString(PyExc_ValueError, "fill character too large");
+        return 0;
+    }
+
+    return 1;
+}
+
+/* Calculate the padding needed. */
+static void
+calc_padding(Py_ssize_t nchars, Py_ssize_t width, Py_UCS4 align,
+             Py_ssize_t *n_lpadding, Py_ssize_t *n_rpadding,
+             Py_ssize_t *n_total)
+{
+    if (width >= 0) {
+        if (nchars > width)
+            *n_total = nchars;
+        else
+            *n_total = width;
+    }
+    else {
+        /* not specified, use all of the chars and no more */
+        *n_total = nchars;
+    }
+
+    /* Figure out how much leading space we need, based on the
+       aligning */
+    if (align == '>')
+        *n_lpadding = *n_total - nchars;
+    else if (align == '^')
+        *n_lpadding = (*n_total - nchars) / 2;
+    else if (align == '<' || align == '=')
+        *n_lpadding = 0;
+    else {
+        /* We should never have an unspecified alignment. */
+        *n_lpadding = 0;
+        assert(0);
+    }
+
+    *n_rpadding = *n_total - nchars - *n_lpadding;
+}
+
+static void
+unicode_fill(PyObject *str, Py_ssize_t start, Py_ssize_t end, Py_UCS4 ch)
+{
+    int kind = PyUnicode_KIND(str);
+    void *data = PyUnicode_DATA(str);
+    while (start < end)
+        PyUnicode_WRITE(kind, data, start++, ch);
+}
+
+/* Do the padding, and return a pointer to where the caller-supplied
+   content goes. */
+static Py_ssize_t
+fill_padding(PyObject *s, Py_ssize_t start, Py_ssize_t nchars,
+             Py_UCS4 fill_char, Py_ssize_t n_lpadding,
+             Py_ssize_t n_rpadding)
+{
+    /* Pad on left. */
+    if (n_lpadding)
+        unicode_fill(s, start, start + n_lpadding, fill_char);
+
+    /* Pad on right. */
+    if (n_rpadding)
+        unicode_fill(s, start + nchars + n_lpadding, 
+                     start + nchars + n_lpadding + n_rpadding, fill_char);
+
+    /* Pointer to the user content. */
+    return start + n_lpadding;
+}
+
+/************************************************************************/
+/*********** common routines for numeric formatting *********************/
+/************************************************************************/
+
+/* Locale type codes. */
+#define LT_CURRENT_LOCALE 0
+#define LT_DEFAULT_LOCALE 1
+#define LT_NO_LOCALE 2
+
+/* Locale info needed for formatting integers and the part of floats
+   before and including the decimal. Note that locales only support
+   8-bit chars, not unicode. */
+typedef struct {
+    char *decimal_point;
+    char *thousands_sep;
+    char *grouping;
+} LocaleInfo;
+
+/* describes the layout for an integer, see the comment in
+   calc_number_widths() for details */
+typedef struct {
+    Py_ssize_t n_lpadding;
+    Py_ssize_t n_prefix;
+    Py_ssize_t n_spadding;
+    Py_ssize_t n_rpadding;
+    char sign;
+    Py_ssize_t n_sign;      /* number of digits needed for sign (0/1) */
+    Py_ssize_t n_grouped_digits; /* Space taken up by the digits, including
+                                    any grouping chars. */
+    Py_ssize_t n_decimal;   /* 0 if only an integer */
+    Py_ssize_t n_remainder; /* Digits in decimal and/or exponent part,
+                               excluding the decimal itself, if
+                               present. */
+
+    /* These 2 are not the widths of fields, but are needed by
+       STRINGLIB_GROUPING. */
+    Py_ssize_t n_digits;    /* The number of digits before a decimal
+                               or exponent. */
+    Py_ssize_t n_min_width; /* The min_width we used when we computed
+                               the n_grouped_digits width. */
+} NumberFieldWidths;
+
+
+/* Given a number of the form:
+   digits[remainder]
+   where ptr points to the start and end points to the end, find where
+    the integer part ends. This could be a decimal, an exponent, both,
+    or neither.
+   If a decimal point is present, set *has_decimal and increment
+    remainder beyond it.
+   Results are undefined (but shouldn't crash) for improperly
+    formatted strings.
+*/
+static void
+parse_number(PyObject *s, Py_ssize_t pos, Py_ssize_t end,
+             Py_ssize_t *n_remainder, int *has_decimal)
+{
+    Py_ssize_t remainder;
+
+    while (pos<end && isdigit(PyUnicode_READ_CHAR(s, pos)))
+        ++pos;
+    remainder = pos;
+
+    /* Does remainder start with a decimal point? */
+    *has_decimal = pos<end && PyUnicode_READ_CHAR(s, remainder) == '.';
+
+    /* Skip the decimal point. */
+    if (*has_decimal)
+        remainder++;
+
+    *n_remainder = end - remainder;
+}
+
+/* not all fields of format are used.  for example, precision is
+   unused.  should this take discrete params in order to be more clear
+   about what it does?  or is passing a single format parameter easier
+   and more efficient enough to justify a little obfuscation? */
+static Py_ssize_t
+calc_number_widths(NumberFieldWidths *spec, Py_ssize_t n_prefix,
+                   Py_UCS4 sign_char, PyObject *number, Py_ssize_t n_start,
+                   Py_ssize_t n_end, Py_ssize_t n_remainder,
+                   int has_decimal, const LocaleInfo *locale,
+                   const InternalFormatSpec *format)
+{
+    Py_ssize_t n_non_digit_non_padding;
+    Py_ssize_t n_padding;
+
+    spec->n_digits = n_end - n_start - n_remainder - (has_decimal?1:0);
+    spec->n_lpadding = 0;
+    spec->n_prefix = n_prefix;
+    spec->n_decimal = has_decimal ? strlen(locale->decimal_point) : 0;
+    spec->n_remainder = n_remainder;
+    spec->n_spadding = 0;
+    spec->n_rpadding = 0;
+    spec->sign = '\0';
+    spec->n_sign = 0;
+
+    /* the output will look like:
+       |                                                                                         |
+       | <lpadding> <sign> <prefix> <spadding> <grouped_digits> <decimal> <remainder> <rpadding> |
+       |                                                                                         |
+
+       sign is computed from format->sign and the actual
+       sign of the number
+
+       prefix is given (it's for the '0x' prefix)
+
+       digits is already known
+
+       the total width is either given, or computed from the
+       actual digits
+
+       only one of lpadding, spadding, and rpadding can be non-zero,
+       and it's calculated from the width and other fields
+    */
+
+    /* compute the various parts we're going to write */
+    switch (format->sign) {
+    case '+':
+        /* always put a + or - */
+        spec->n_sign = 1;
+        spec->sign = (sign_char == '-' ? '-' : '+');
+        break;
+    case ' ':
+        spec->n_sign = 1;
+        spec->sign = (sign_char == '-' ? '-' : ' ');
+        break;
+    default:
+        /* Not specified, or the default (-) */
+        if (sign_char == '-') {
+            spec->n_sign = 1;
+            spec->sign = '-';
+        }
+    }
+
+    /* The number of chars used for non-digits and non-padding. */
+    n_non_digit_non_padding = spec->n_sign + spec->n_prefix + spec->n_decimal +
+        spec->n_remainder;
+
+    /* min_width can go negative, that's okay. format->width == -1 means
+       we don't care. */
+    if (format->fill_char == '0' && format->align == '=')
+        spec->n_min_width = format->width - n_non_digit_non_padding;
+    else
+        spec->n_min_width = 0;
+
+    if (spec->n_digits == 0)
+        /* This case only occurs when using 'c' formatting, we need
+           to special case it because the grouping code always wants
+           to have at least one character. */
+        spec->n_grouped_digits = 0;
+    else
+        spec->n_grouped_digits = _PyUnicode_InsertThousandsGrouping(
+            PyUnicode_1BYTE_KIND, NULL, 0, NULL, 
+            spec->n_digits, spec->n_min_width,
+            locale->grouping, locale->thousands_sep);
+
+    /* Given the desired width and the total of digit and non-digit
+       space we consume, see if we need any padding. format->width can
+       be negative (meaning no padding), but this code still works in
+       that case. */
+    n_padding = format->width -
+                        (n_non_digit_non_padding + spec->n_grouped_digits);
+    if (n_padding > 0) {
+        /* Some padding is needed. Determine if it's left, space, or right. */
+        switch (format->align) {
+        case '<':
+            spec->n_rpadding = n_padding;
+            break;
+        case '^':
+            spec->n_lpadding = n_padding / 2;
+            spec->n_rpadding = n_padding - spec->n_lpadding;
+            break;
+        case '=':
+            spec->n_spadding = n_padding;
+            break;
+        case '>':
+            spec->n_lpadding = n_padding;
+            break;
+        default:
+            /* Shouldn't get here, but treat it as '>' */
+            spec->n_lpadding = n_padding;
+            assert(0);
+            break;
+        }
+    }
+    return spec->n_lpadding + spec->n_sign + spec->n_prefix +
+        spec->n_spadding + spec->n_grouped_digits + spec->n_decimal +
+        spec->n_remainder + spec->n_rpadding;
+}
+
+/* Fill in the digit parts of a numbers's string representation,
+   as determined in calc_number_widths().
+   No error checking, since we know the buffer is the correct size. */
+static void
+fill_number(PyObject *out, Py_ssize_t pos, const NumberFieldWidths *spec,
+            PyObject *digits, Py_ssize_t d_start, Py_ssize_t d_end,
+            PyObject *prefix, Py_ssize_t p_start, Py_UCS4 fill_char,
+            LocaleInfo *locale, int toupper)
+{
+    /* Used to keep track of digits, decimal, and remainder. */
+    Py_ssize_t d_pos = d_start;
+    unsigned int kind = PyUnicode_KIND(out);
+    void *data = PyUnicode_DATA(out);
+
+#ifndef NDEBUG
+    Py_ssize_t r;
+#endif
+
+    if (spec->n_lpadding) {
+        unicode_fill(out, pos, pos + spec->n_lpadding, fill_char);
+        pos += spec->n_lpadding;
+    }
+    if (spec->n_sign == 1) {
+        PyUnicode_WRITE(kind, data, pos++, spec->sign);
+    }
+    if (spec->n_prefix) {
+        PyUnicode_CopyCharacters(out, pos, prefix, p_start, spec->n_prefix);
+        if (toupper) {
+            Py_ssize_t t;
+            /* XXX if the upper-case prefix is wider than the target
+               buffer, the caller should have allocated a wider string,
+               but currently doesn't. */
+            for (t = 0; t < spec->n_prefix; ++t)
+                PyUnicode_WRITE(kind, data, pos + t,
+                                Py_UNICODE_TOUPPER(
+                                    PyUnicode_READ(kind, data, pos + t)));
+        }
+        pos += spec->n_prefix;
+    }
+    if (spec->n_spadding) {
+        unicode_fill(out, pos, pos + spec->n_spadding, fill_char);
+        pos += spec->n_spadding;
+    }
+
+    /* Only for type 'c' special case, it has no digits. */
+    if (spec->n_digits != 0) {
+        /* Fill the digits with InsertThousandsGrouping. */
+        char *pdigits = PyUnicode_DATA(digits);
+        if (PyUnicode_KIND(digits) < kind) {
+            pdigits = _PyUnicode_AsKind(digits, kind);
+            if (pdigits == NULL) {
+                /* XXX report exception */
+                Py_FatalError("out of memory");
+                return;
+            }
+        }
+#ifndef NDEBUG
+        r =
+#endif
+            _PyUnicode_InsertThousandsGrouping(
+                kind,
+                (char*)data + PyUnicode_KIND_SIZE(kind, pos),
+                spec->n_grouped_digits,
+                pdigits + PyUnicode_KIND_SIZE(kind, d_pos),
+                spec->n_digits, spec->n_min_width,
+                locale->grouping, locale->thousands_sep);
+#ifndef NDEBUG
+        assert(r == spec->n_grouped_digits);
+#endif
+        if (PyUnicode_KIND(digits) < kind)
+            PyMem_Free(pdigits);
+        d_pos += spec->n_digits;
+    }
+    if (toupper) {
+        Py_ssize_t t;
+        for (t = 0; t < spec->n_grouped_digits; ++t)
+            PyUnicode_WRITE(kind, data, pos + t,
+                            Py_UNICODE_TOUPPER(
+                                PyUnicode_READ(kind, data, pos + t)));
+    }
+    pos += spec->n_grouped_digits;
+
+    if (spec->n_decimal) {
+        Py_ssize_t t;
+        for (t = 0; t < spec->n_decimal; ++t)
+            PyUnicode_WRITE(kind, data, pos + t,
+                            locale->decimal_point[t]);
+        pos += spec->n_decimal;
+        d_pos += 1;
+    }
+
+    if (spec->n_remainder) {
+        PyUnicode_CopyCharacters(out, pos, digits, d_pos, spec->n_remainder);
+        pos += spec->n_remainder;
+        d_pos += spec->n_remainder;
+    }
+
+    if (spec->n_rpadding) {
+        unicode_fill(out, pos, pos + spec->n_rpadding, fill_char);
+        pos += spec->n_rpadding;
+    }
+}
+
+static char no_grouping[1] = {CHAR_MAX};
+
+/* Find the decimal point character(s?), thousands_separator(s?), and
+   grouping description, either for the current locale if type is
+   LT_CURRENT_LOCALE, a hard-coded locale if LT_DEFAULT_LOCALE, or
+   none if LT_NO_LOCALE. */
+static void
+get_locale_info(int type, LocaleInfo *locale_info)
+{
+    switch (type) {
+    case LT_CURRENT_LOCALE: {
+        struct lconv *locale_data = localeconv();
+        locale_info->decimal_point = locale_data->decimal_point;
+        locale_info->thousands_sep = locale_data->thousands_sep;
+        locale_info->grouping = locale_data->grouping;
+        break;
+    }
+    case LT_DEFAULT_LOCALE:
+        locale_info->decimal_point = ".";
+        locale_info->thousands_sep = ",";
+        locale_info->grouping = "\3"; /* Group every 3 characters.  The
+                                         (implicit) trailing 0 means repeat
+                                         infinitely. */
+        break;
+    case LT_NO_LOCALE:
+        locale_info->decimal_point = ".";
+        locale_info->thousands_sep = "";
+        locale_info->grouping = no_grouping;
+        break;
+    default:
+        assert(0);
+    }
+}
+
+/************************************************************************/
+/*********** string formatting ******************************************/
+/************************************************************************/
+
+static PyObject *
+format_string_internal(PyObject *value, const InternalFormatSpec *format)
+{
+    Py_ssize_t lpad;
+    Py_ssize_t rpad;
+    Py_ssize_t total;
+    Py_ssize_t pos;
+    Py_ssize_t len = PyUnicode_GET_SIZE(value);
+    PyObject *result = NULL;
+    int maxchar = 127;
+
+    /* sign is not allowed on strings */
+    if (format->sign != '\0') {
+        PyErr_SetString(PyExc_ValueError,
+                        "Sign not allowed in string format specifier");
+        goto done;
+    }
+
+    /* alternate is not allowed on strings */
+    if (format->alternate) {
+        PyErr_SetString(PyExc_ValueError,
+                        "Alternate form (#) not allowed in string format "
+                        "specifier");
+        goto done;
+    }
+
+    /* '=' alignment not allowed on strings */
+    if (format->align == '=') {
+        PyErr_SetString(PyExc_ValueError,
+                        "'=' alignment not allowed "
+                        "in string format specifier");
+        goto done;
+    }
+
+    /* if precision is specified, output no more that format.precision
+       characters */
+    if (format->precision >= 0 && len >= format->precision) {
+        len = format->precision;
+    }
+
+    calc_padding(len, format->width, format->align, &lpad, &rpad, &total);
+
+    /* allocate the resulting string */
+    result = PyUnicode_New(total, maxchar);
+    if (result == NULL)
+        goto done;
+
+    /* Write into that space. First the padding. */
+    pos = fill_padding(result, 0, len,
+                       format->fill_char=='\0'?' ':format->fill_char,
+                       lpad, rpad);
+
+    /* Then the source string. */
+    PyUnicode_CopyCharacters(result, pos, value, 0, len);
+
+done:
+    return result;
+}
+
+
+/************************************************************************/
+/*********** long formatting ********************************************/
+/************************************************************************/
+
+typedef PyObject*
+(*IntOrLongToString)(PyObject *value, int base);
+
+static PyObject *
+format_int_or_long_internal(PyObject *value, const InternalFormatSpec *format,
+                            IntOrLongToString tostring)
+{
+    PyObject *result = NULL;
+    int maxchar = 127;
+    PyObject *tmp = NULL;
+    Py_ssize_t inumeric_chars;
+    Py_UCS4 sign_char = '\0';
+    Py_ssize_t n_digits;       /* count of digits need from the computed
+                                  string */
+    Py_ssize_t n_remainder = 0; /* Used only for 'c' formatting, which
+                                   produces non-digits */
+    Py_ssize_t n_prefix = 0;   /* Count of prefix chars, (e.g., '0x') */
+    Py_ssize_t n_total;
+    Py_ssize_t prefix;
+    NumberFieldWidths spec;
+    long x;
+
+    /* Locale settings, either from the actual locale or
+       from a hard-code pseudo-locale */
+    LocaleInfo locale;
+
+    /* no precision allowed on integers */
+    if (format->precision != -1) {
+        PyErr_SetString(PyExc_ValueError,
+                        "Precision not allowed in integer format specifier");
+        goto done;
+    }
+
+    /* special case for character formatting */
+    if (format->type == 'c') {
+        /* error to specify a sign */
+        if (format->sign != '\0') {
+            PyErr_SetString(PyExc_ValueError,
+                            "Sign not allowed with integer"
+                            " format specifier 'c'");
+            goto done;
+        }
+
+        /* taken from unicodeobject.c formatchar() */
+        /* Integer input truncated to a character */
+/* XXX: won't work for int */
+        x = PyLong_AsLong(value);
+        if (x == -1 && PyErr_Occurred())
+            goto done;
+        if (x < 0 || x > 0x10ffff) {
+            PyErr_SetString(PyExc_OverflowError,
+                            "%c arg not in range(0x110000) "
+                            "(wide Python build)");
+            goto done;
+        }
+        tmp = PyUnicode_FromOrdinal(x);
+        inumeric_chars = 0;
+        n_digits = 1;
+        if (x > maxchar)
+            maxchar = x;
+
+        /* As a sort-of hack, we tell calc_number_widths that we only
+           have "remainder" characters. calc_number_widths thinks
+           these are characters that don't get formatted, only copied
+           into the output string. We do this for 'c' formatting,
+           because the characters are likely to be non-digits. */
+        n_remainder = 1;
+    }
+    else {
+        int base;
+        int leading_chars_to_skip = 0;  /* Number of characters added by
+                                           PyNumber_ToBase that we want to
+                                           skip over. */
+
+        /* Compute the base and how many characters will be added by
+           PyNumber_ToBase */
+        switch (format->type) {
+        case 'b':
+            base = 2;
+            leading_chars_to_skip = 2; /* 0b */
+            break;
+        case 'o':
+            base = 8;
+            leading_chars_to_skip = 2; /* 0o */
+            break;
+        case 'x':
+        case 'X':
+            base = 16;
+            leading_chars_to_skip = 2; /* 0x */
+            break;
+        default:  /* shouldn't be needed, but stops a compiler warning */
+        case 'd':
+        case 'n':
+            base = 10;
+            break;
+        }
+
+        /* The number of prefix chars is the same as the leading
+           chars to skip */
+        if (format->alternate)
+            n_prefix = leading_chars_to_skip;
+
+        /* Do the hard part, converting to a string in a given base */
+        tmp = tostring(value, base);
+        if (tmp == NULL || PyUnicode_READY(tmp) == -1)
+            goto done;
+
+        inumeric_chars = 0;
+        n_digits = PyUnicode_GET_LENGTH(tmp);
+
+        prefix = inumeric_chars;
+
+        /* Is a sign character present in the output?  If so, remember it
+           and skip it */
+        if (PyUnicode_READ_CHAR(tmp, inumeric_chars) == '-') {
+            sign_char = '-';
+            ++prefix;
+            ++leading_chars_to_skip;
+        }
+
+        /* Skip over the leading chars (0x, 0b, etc.) */
+        n_digits -= leading_chars_to_skip;
+        inumeric_chars += leading_chars_to_skip;
+    }
+
+    /* Determine the grouping, separator, and decimal point, if any. */
+    get_locale_info(format->type == 'n' ? LT_CURRENT_LOCALE :
+                    (format->thousands_separators ?
+                     LT_DEFAULT_LOCALE :
+                     LT_NO_LOCALE),
+                    &locale);
+
+    /* Calculate how much memory we'll need. */
+    n_total = calc_number_widths(&spec, n_prefix, sign_char, tmp, inumeric_chars,
+                                 inumeric_chars + n_digits, n_remainder, 0, &locale, format);
+
+    /* Allocate the memory. */
+    result = PyUnicode_New(n_total, maxchar);
+    if (!result)
+        goto done;
+
+    /* Populate the memory. */
+    fill_number(result, 0, &spec, tmp, inumeric_chars, inumeric_chars + n_digits,
+                tmp, prefix,
+                format->fill_char == '\0' ? ' ' : format->fill_char,
+                &locale, format->type == 'X');
+
+done:
+    Py_XDECREF(tmp);
+    return result;
+}
+
+/************************************************************************/
+/*********** float formatting *******************************************/
+/************************************************************************/
+
+static PyObject*
+strtounicode(char *charbuffer, Py_ssize_t len)
+{
+    return PyUnicode_FromKindAndData(PyUnicode_1BYTE_KIND, charbuffer, len);
+}
+
+/* much of this is taken from unicodeobject.c */
+static PyObject *
+format_float_internal(PyObject *value,
+                      const InternalFormatSpec *format)
+{
+    char *buf = NULL;       /* buffer returned from PyOS_double_to_string */
+    Py_ssize_t n_digits;
+    Py_ssize_t n_remainder;
+    Py_ssize_t n_total;
+    int has_decimal;
+    double val;
+    Py_ssize_t precision = format->precision;
+    Py_ssize_t default_precision = 6;
+    Py_UCS4 type = format->type;
+    int add_pct = 0;
+    Py_ssize_t index;
+    NumberFieldWidths spec;
+    int flags = 0;
+    PyObject *result = NULL;
+    int maxchar = 127;
+    Py_UCS4 sign_char = '\0';
+    int float_type; /* Used to see if we have a nan, inf, or regular float. */
+    PyObject *unicode_tmp = NULL;
+
+    /* Locale settings, either from the actual locale or
+       from a hard-code pseudo-locale */
+    LocaleInfo locale;
+
+    if (format->alternate)
+        flags |= Py_DTSF_ALT;
+
+    if (type == '\0') {
+        /* Omitted type specifier.  Behaves in the same way as repr(x)
+           and str(x) if no precision is given, else like 'g', but with
+           at least one digit after the decimal point. */
+        flags |= Py_DTSF_ADD_DOT_0;
+        type = 'r';
+        default_precision = 0;
+    }
+
+    if (type == 'n')
+        /* 'n' is the same as 'g', except for the locale used to
+           format the result. We take care of that later. */
+        type = 'g';
+
+    val = PyFloat_AsDouble(value);
+    if (val == -1.0 && PyErr_Occurred())
+        goto done;
+
+    if (type == '%') {
+        type = 'f';
+        val *= 100;
+        add_pct = 1;
+    }
+
+    if (precision < 0)
+        precision = default_precision;
+    else if (type == 'r')
+        type = 'g';
+
+    /* Cast "type", because if we're in unicode we need to pass a
+       8-bit char. This is safe, because we've restricted what "type"
+       can be. */
+    buf = PyOS_double_to_string(val, (char)type, precision, flags,
+                                &float_type);
+    if (buf == NULL)
+        goto done;
+    n_digits = strlen(buf);
+
+    if (add_pct) {
+        /* We know that buf has a trailing zero (since we just called
+           strlen() on it), and we don't use that fact any more. So we
+           can just write over the trailing zero. */
+        buf[n_digits] = '%';
+        n_digits += 1;
+    }
+
+    /* Since there is no unicode version of PyOS_double_to_string,
+       just use the 8 bit version and then convert to unicode. */
+    unicode_tmp = strtounicode(buf, n_digits);
+    if (unicode_tmp == NULL)
+        goto done;
+    index = 0;
+
+    /* Is a sign character present in the output?  If so, remember it
+       and skip it */
+    if (PyUnicode_READ_CHAR(unicode_tmp, index) == '-') {
+        sign_char = '-';
+        ++index;
+        --n_digits;
+    }
+
+    /* Determine if we have any "remainder" (after the digits, might include
+       decimal or exponent or both (or neither)) */
+    parse_number(unicode_tmp, index, index + n_digits, &n_remainder, &has_decimal);
+
+    /* Determine the grouping, separator, and decimal point, if any. */
+    get_locale_info(format->type == 'n' ? LT_CURRENT_LOCALE :
+                    (format->thousands_separators ?
+                     LT_DEFAULT_LOCALE :
+                     LT_NO_LOCALE),
+                    &locale);
+
+    /* Calculate how much memory we'll need. */
+    n_total = calc_number_widths(&spec, 0, sign_char, unicode_tmp, index, 
+                                 index + n_digits, n_remainder, has_decimal,
+                                 &locale, format);
+
+    /* Allocate the memory. */
+    result = PyUnicode_New(n_total, maxchar);
+    if (result == NULL)
+        goto done;
+
+    /* Populate the memory. */
+    fill_number(result, 0, &spec, unicode_tmp, index, index + n_digits,
+                NULL, 0,
+                format->fill_char == '\0' ? ' ' : format->fill_char, &locale,
+                0);
+
+done:
+    PyMem_Free(buf);
+    Py_DECREF(unicode_tmp);
+    return result;
+}
+
+/************************************************************************/
+/*********** complex formatting *****************************************/
+/************************************************************************/
+
+static PyObject *
+format_complex_internal(PyObject *value,
+                        const InternalFormatSpec *format)
+{
+    double re;
+    double im;
+    char *re_buf = NULL;       /* buffer returned from PyOS_double_to_string */
+    char *im_buf = NULL;       /* buffer returned from PyOS_double_to_string */
+
+    InternalFormatSpec tmp_format = *format;
+    Py_ssize_t n_re_digits;
+    Py_ssize_t n_im_digits;
+    Py_ssize_t n_re_remainder;
+    Py_ssize_t n_im_remainder;
+    Py_ssize_t n_re_total;
+    Py_ssize_t n_im_total;
+    int re_has_decimal;
+    int im_has_decimal;
+    Py_ssize_t precision = format->precision;
+    Py_ssize_t default_precision = 6;
+    Py_UCS4 type = format->type;
+    Py_ssize_t i_re;
+    Py_ssize_t i_im;
+    NumberFieldWidths re_spec;
+    NumberFieldWidths im_spec;
+    int flags = 0;
+    PyObject *result = NULL;
+    int maxchar = 127;
+    int rkind;
+    void *rdata;
+    Py_ssize_t index;
+    Py_UCS4 re_sign_char = '\0';
+    Py_UCS4 im_sign_char = '\0';
+    int re_float_type; /* Used to see if we have a nan, inf, or regular float. */
+    int im_float_type;
+    int add_parens = 0;
+    int skip_re = 0;
+    Py_ssize_t lpad;
+    Py_ssize_t rpad;
+    Py_ssize_t total;
+    PyObject *re_unicode_tmp = NULL;
+    PyObject *im_unicode_tmp = NULL;
+
+    /* Locale settings, either from the actual locale or
+       from a hard-code pseudo-locale */
+    LocaleInfo locale;
+
+    /* Zero padding is not allowed. */
+    if (format->fill_char == '0') {
+        PyErr_SetString(PyExc_ValueError,
+                        "Zero padding is not allowed in complex format "
+                        "specifier");
+        goto done;
+    }
+
+    /* Neither is '=' alignment . */
+    if (format->align == '=') {
+        PyErr_SetString(PyExc_ValueError,
+                        "'=' alignment flag is not allowed in complex format "
+                        "specifier");
+        goto done;
+    }
+
+    re = PyComplex_RealAsDouble(value);
+    if (re == -1.0 && PyErr_Occurred())
+        goto done;
+    im = PyComplex_ImagAsDouble(value);
+    if (im == -1.0 && PyErr_Occurred())
+        goto done;
+
+    if (format->alternate)
+        flags |= Py_DTSF_ALT;
+
+    if (type == '\0') {
+        /* Omitted type specifier. Should be like str(self). */
+        type = 'r';
+        default_precision = 0;
+        if (re == 0.0 && copysign(1.0, re) == 1.0)
+            skip_re = 1;
+        else
+            add_parens = 1;
+    }
+
+    if (type == 'n')
+        /* 'n' is the same as 'g', except for the locale used to
+           format the result. We take care of that later. */
+        type = 'g';
+
+    if (precision < 0)
+        precision = default_precision;
+    else if (type == 'r')
+        type = 'g';
+
+    /* Cast "type", because if we're in unicode we need to pass a
+       8-bit char. This is safe, because we've restricted what "type"
+       can be. */
+    re_buf = PyOS_double_to_string(re, (char)type, precision, flags,
+                                   &re_float_type);
+    if (re_buf == NULL)
+        goto done;
+    im_buf = PyOS_double_to_string(im, (char)type, precision, flags,
+                                   &im_float_type);
+    if (im_buf == NULL)
+        goto done;
+
+    n_re_digits = strlen(re_buf);
+    n_im_digits = strlen(im_buf);
+
+    /* Since there is no unicode version of PyOS_double_to_string,
+       just use the 8 bit version and then convert to unicode. */
+    re_unicode_tmp = strtounicode(re_buf, n_re_digits);
+    if (re_unicode_tmp == NULL)
+        goto done;
+    i_re = 0;
+
+    im_unicode_tmp = strtounicode(im_buf, n_im_digits);
+    if (im_unicode_tmp == NULL)
+        goto done;
+    i_im = 0;
+
+    /* Is a sign character present in the output?  If so, remember it
+       and skip it */
+    if (PyUnicode_READ_CHAR(re_unicode_tmp, i_re) == '-') {
+        re_sign_char = '-';
+        ++i_re;
+        --n_re_digits;
+    }
+    if (PyUnicode_READ_CHAR(im_unicode_tmp, i_im) == '-') {
+        im_sign_char = '-';
+        ++i_im;
+        --n_im_digits;
+    }
+
+    /* Determine if we have any "remainder" (after the digits, might include
+       decimal or exponent or both (or neither)) */
+    parse_number(re_unicode_tmp, i_re, i_re + n_re_digits, 
+                 &n_re_remainder, &re_has_decimal);
+    parse_number(im_unicode_tmp, i_im, i_im + n_im_digits, 
+                 &n_im_remainder, &im_has_decimal);
+
+    /* Determine the grouping, separator, and decimal point, if any. */
+    get_locale_info(format->type == 'n' ? LT_CURRENT_LOCALE :
+                    (format->thousands_separators ?
+                     LT_DEFAULT_LOCALE :
+                     LT_NO_LOCALE),
+                    &locale);
+
+    /* Turn off any padding. We'll do it later after we've composed
+       the numbers without padding. */
+    tmp_format.fill_char = '\0';
+    tmp_format.align = '<';
+    tmp_format.width = -1;
+
+    /* Calculate how much memory we'll need. */
+    n_re_total = calc_number_widths(&re_spec, 0, re_sign_char, re_unicode_tmp,
+                                    i_re, i_re + n_re_digits, n_re_remainder,
+                                    re_has_decimal, &locale, &tmp_format);
+
+    /* Same formatting, but always include a sign, unless the real part is
+     * going to be omitted, in which case we use whatever sign convention was
+     * requested by the original format. */
+    if (!skip_re)
+        tmp_format.sign = '+';
+    n_im_total = calc_number_widths(&im_spec, 0, im_sign_char, im_unicode_tmp,
+                                    i_im, i_im + n_im_digits, n_im_remainder,
+                                    im_has_decimal, &locale, &tmp_format);
+
+    if (skip_re)
+        n_re_total = 0;
+
+    /* Add 1 for the 'j', and optionally 2 for parens. */
+    calc_padding(n_re_total + n_im_total + 1 + add_parens * 2,
+                 format->width, format->align, &lpad, &rpad, &total);
+
+    result = PyUnicode_New(total, maxchar);
+    if (result == NULL)
+        goto done;
+    rkind = PyUnicode_KIND(result);
+    rdata = PyUnicode_DATA(result);
+
+    /* Populate the memory. First, the padding. */
+    index = fill_padding(result, 0,
+                         n_re_total + n_im_total + 1 + add_parens * 2,
+                         format->fill_char=='\0' ? ' ' : format->fill_char,
+                         lpad, rpad);
+
+    if (add_parens)
+        PyUnicode_WRITE(rkind, rdata, index++, '(');
+
+    if (!skip_re) {
+        fill_number(result, index, &re_spec, re_unicode_tmp, 
+                    i_re, i_re + n_re_digits, NULL, 0, 0, &locale, 0);
+        index += n_re_total;
+    }
+    fill_number(result, index, &im_spec, im_unicode_tmp,
+                i_im, i_im + n_im_digits, NULL, 0, 0, &locale, 0);
+    index += n_im_total;
+    PyUnicode_WRITE(rkind, rdata, index++, 'j');
+
+    if (add_parens)
+        PyUnicode_WRITE(rkind, rdata, index++, ')');
+
+done:
+    PyMem_Free(re_buf);
+    PyMem_Free(im_buf);
+    Py_XDECREF(re_unicode_tmp);
+    Py_XDECREF(im_unicode_tmp);
+    return result;
+}
+
+/************************************************************************/
+/*********** built in formatters ****************************************/
+/************************************************************************/
+PyObject *
+_PyUnicode_FormatAdvanced(PyObject *obj,
+                          PyObject *format_spec,
+                          Py_ssize_t start, Py_ssize_t end)
+{
+    InternalFormatSpec format;
+    PyObject *result = NULL;
+
+    /* check for the special case of zero length format spec, make
+       it equivalent to str(obj) */
+    if (start == end) {
+        result = PyObject_Str(obj);
+        goto done;
+    }
+
+    /* parse the format_spec */
+    if (!parse_internal_render_format_spec(format_spec, start, end,
+                                           &format, 's', '<'))
+        goto done;
+
+    /* type conversion? */
+    switch (format.type) {
+    case 's':
+        /* no type conversion needed, already a string.  do the formatting */
+        result = format_string_internal(obj, &format);
+        break;
+    default:
+        /* unknown */
+        unknown_presentation_type(format.type, obj->ob_type->tp_name);
+        goto done;
+    }
+
+done:
+    return result;
+}
+
+static PyObject*
+format_int_or_long(PyObject* obj, PyObject* format_spec,
+                   Py_ssize_t start, Py_ssize_t end,
+                   IntOrLongToString tostring)
+{
+    PyObject *result = NULL;
+    PyObject *tmp = NULL;
+    InternalFormatSpec format;
+
+    /* check for the special case of zero length format spec, make
+       it equivalent to str(obj) */
+    if (start == end) {
+        result = PyObject_Str(obj);
+        goto done;
+    }
+
+    /* parse the format_spec */
+    if (!parse_internal_render_format_spec(format_spec, start, end,
+                                           &format, 'd', '>'))
+        goto done;
+
+    /* type conversion? */
+    switch (format.type) {
+    case 'b':
+    case 'c':
+    case 'd':
+    case 'o':
+    case 'x':
+    case 'X':
+    case 'n':
+        /* no type conversion needed, already an int (or long).  do
+           the formatting */
+            result = format_int_or_long_internal(obj, &format, tostring);
+        break;
+
+    case 'e':
+    case 'E':
+    case 'f':
+    case 'F':
+    case 'g':
+    case 'G':
+    case '%':
+        /* convert to float */
+        tmp = PyNumber_Float(obj);
+        if (tmp == NULL)
+            goto done;
+        result = format_float_internal(tmp, &format);
+        break;
+
+    default:
+        /* unknown */
+        unknown_presentation_type(format.type, obj->ob_type->tp_name);
+        goto done;
+    }
+
+done:
+    Py_XDECREF(tmp);
+    return result;
+}
+
+/* Need to define long_format as a function that will convert a long
+   to a string.  In 3.0, _PyLong_Format has the correct signature. */
+#define long_format _PyLong_Format
+
+PyObject *
+_PyLong_FormatAdvanced(PyObject *obj,
+                       PyObject *format_spec,
+                       Py_ssize_t start, Py_ssize_t end)
+{
+    return format_int_or_long(obj, format_spec, start, end,
+                              long_format);
+}
+
+PyObject *
+_PyFloat_FormatAdvanced(PyObject *obj,
+                        PyObject *format_spec,
+                        Py_ssize_t start, Py_ssize_t end)
+{
+    PyObject *result = NULL;
+    InternalFormatSpec format;
+
+    /* check for the special case of zero length format spec, make
+       it equivalent to str(obj) */
+    if (start == end) {
+        result = PyObject_Str(obj);
+        goto done;
+    }
+
+    /* parse the format_spec */
+    if (!parse_internal_render_format_spec(format_spec, start, end,
+                                           &format, '\0', '>'))
+        goto done;
+
+    /* type conversion? */
+    switch (format.type) {
+    case '\0': /* No format code: like 'g', but with at least one decimal. */
+    case 'e':
+    case 'E':
+    case 'f':
+    case 'F':
+    case 'g':
+    case 'G':
+    case 'n':
+    case '%':
+        /* no conversion, already a float.  do the formatting */
+        result = format_float_internal(obj, &format);
+        break;
+
+    default:
+        /* unknown */
+        unknown_presentation_type(format.type, obj->ob_type->tp_name);
+        goto done;
+    }
+
+done:
+    return result;
+}
+
+PyObject *
+_PyComplex_FormatAdvanced(PyObject *obj,
+                          PyObject *format_spec,
+                          Py_ssize_t start, Py_ssize_t end)
+{
+    PyObject *result = NULL;
+    InternalFormatSpec format;
+
+    /* check for the special case of zero length format spec, make
+       it equivalent to str(obj) */
+    if (start == end) {
+        result = PyObject_Str(obj);
+        goto done;
+    }
+
+    /* parse the format_spec */
+    if (!parse_internal_render_format_spec(format_spec, start, end,
+                                           &format, '\0', '>'))
+        goto done;
+
+    /* type conversion? */
+    switch (format.type) {
+    case '\0': /* No format code: like 'g', but with at least one decimal. */
+    case 'e':
+    case 'E':
+    case 'f':
+    case 'F':
+    case 'g':
+    case 'G':
+    case 'n':
+        /* no conversion, already a complex.  do the formatting */
+        result = format_complex_internal(obj, &format);
+        break;
+
+    default:
+        /* unknown */
+        unknown_presentation_type(format.type, obj->ob_type->tp_name);
+        goto done;
+    }
+
+done:
+    return result;
+}